Transcript

1.
Smruti Ranjan Pradhan et al Int. Journal of Engineering Research and Application
ISSN : 2248-9622, Vol. 3, Issue 6, Nov-Dec 2013, pp.433-437
RESEARCH ARTICLE
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OPEN ACCESS
Design of Standalone Hybrid Biomass & PV System of an OffGrid House in a Remote Area
Smruti Ranjan Pradhan1, Prajna Pragatika Bhuyan2, Sangram Keshari Sahoo3,
G.R.K.D.Satya Prasad4
1
(Asst. Professor, GIET, Gunupur, Odisha)
(Asst. Professor, GIET, Gunupur, Odisha)
3
(Asst. Professor, GIET, Gunupur, Odisha)
4
(Assoc. Professor, GIET, Gunupur, Odisha)
2
ABSTRACT
The use of renewable energy sources is becoming very necessary due to the limited reserves of fossil fuels and
global environmental concerns for the production of electrical power generation and utilization. In remote areas,
villages, it is easy to get more amount biomass. Hence by the use of hybrid systems consisting of Biomass and
PV for production of electrical energy in these remote areas can be more economical. If the development of a
computer-based approach for evaluating, the general performance of standalone hybrid PV- Biomass generating
systems are analyzed ,then these results are useful for developing and installing hybrid systems in remote areas
This paper focuses the economical consideration of standalone hybrid systems having PV and Biomass for
electrical production in remote areas. Also in this paper a simulation approach has been suggested for designing
stand alone grid for remote areas. The average solar radiation and quantity of biomass required data are to
predict the general performance of the generating system. The batteries can also be used in this system to store
the extra energy which can further be used for backup. Also the extra power is used to supply to the grid. Here
the simulation is carried out using HOMER software. The results and analysis can used to improve the
development of the proposed model.
Keywords – Biomass, Hybrid system, Homer software, Micro grid, PV array
I.
INTRODUCTION
Many villages in the world live in isolated
areas far from the main utility grid. It is really
impossible their meet by the conventional sources
because of the high cost of transport and the
distribution of energy to this remote areas [1].
Currently, the electric provisioning of these sectors is
done by the hybrid systems of production of electricity
whose diesel generator plays a significant role like
auxiliary source [2]. These hybrid systems involve
combination of different energy sources with wind,
PV, mini hydro, Biomass, fuel cells etc.,
It was shown that the hybrid systems of
energy can in a significant way reduce the total cost of
energy produced, while providing a more reliable
provisioning of electricity by the combination of
Electrical energy plays crucial factor in development
of economical and technological of present society.
Every year the demand of electrical energy is grow
rapidly throughout the world. In India it is very
difficult and also uneconomical to transmit power over
long distances through transmission lines for special
remote villages. Also 70% of its population is live in
rural areas. Generally the production of electrical
energy generally depends on fossil fuels. As a result it
increases CO2 emissions, which are not healthy for
environment concern [2].
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So as to reduce emissions of CO2 and also to meet the
growing needs for generation of electricity we should
adopt the renewable energy by using hybrid systems.
Renewable energy based technology for production of
electricity is suitable to remote and rural areas. So the
use of standalone Hybrid systems using Renewable
energy for production of electricity is more
economical in remote areas[4]. There are many
renewable energy can be implemented in hybrid
systems like solar, wind, hydro, geothermal, biomass
etc. But especially for rural and remote areas it is
economical to use hybrid systems consisting of solar
and biomass once the biomass supply should be
available throughout the year. In most of the remote
areas the manure and crop wastes and other crop based
residues are available at free of cost.
Standalone systems are intended to operate
independent of electric utility. It is not being
connected to main grid. Batteries are used in this
system belongs to lead acid type. The main useful of
this system are it requires lesser maintenance cost and
as well as it is healthy as for environmental
consideration. Generally such type of systems
supports to the distributed generation and connected to
micro grids. In near future the system is favoring to
Distributed generation and micro grids.
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Smruti Ranjan Pradhan et al Int. Journal of Engineering Research and Application
ISSN : 2248-9622, Vol. 3, Issue 6, Nov-Dec 2013, pp.433-437
II.
HYBRID SYSTEMS
A PV – Biomass power system, which is a
combination of a photovoltaic array integrated with a
biomass generator, is a better option for a remote area
which is not connected to the grid and is a best
solution to electrification of remote areas, where
extension of national grid is not a cost effective
option. The system which is analyzing consists of a
PV array, a battery bank, a biomass generator, a
charge controller and a DC/AC converter. In the
design and sizing of the system; the system should be
considered as an autonomous system. Such a
constraint leads to an infinite number of possible
system configurations.
A. PV System:
Sizing a photovoltaic system is an important task
in the system’s design. In the sizing process one has to
take into account three basic factors:
i. The solar insolation of the site and generally the
Metrological data
ii. The daily power consumption (Wh) and types of
the electric loads, and
iii. The storage system to contribute to the system’s
energy independence for a certain period of time
The PV generator is oversized it will have a
big impact in the final cost and the price of the power
produced and in the other hand, the PV-generator is
undersized, problems might occur in meeting the
power demand at any time. The sizing should be
carefully planned, examining various possible PV
system configurations and various models of
components in order to get a cost effective and reliable
system [3].
The amount of solar radiation at a site at any
time, either it is expressed as solar intensity (W/m2) or
solar insolation or radiation in MJ or Wh, is primarily
required to provide answer to the amount of power
produced by the PV generator. The amount of
electrical energy produced by a PV-array depends
primarily on the insolation at a given location and
time. Data on solar insolation are usually given in the
form of global radiation that is beam, direct and
diffuse radiation over a horizontal surface.
B. Biomass power:
Biomass is the amount of living matter in a
given habitat, expressed either as the weight of
organisms per unit area. Biogas is a mixture of gases,
generally carbon dioxide and methane. It is produced
by microorganisms, especially in the absence of
oxygen. This process is called anaerobic process.
Biogas also can develop at the bottom of lakes where
decaying organic matter builds up under wet and
anaerobic conditions. And a biodiesel is made from
vegetable oils and animal fats.
The main factor of choosing this type of
hybrid system consist of biomass is that in remote area
villages it is easily and economically available in the
form of dung of cow, buffalo, goat etc. During the
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cloudy day, the total electricity production can depend
on the biomass.
The most perspective was the building of
biogas plant in a remote area and care has to be taken
that, as there was located large dairy farm. Rest of the
needed feedstock for this cogeneration plant is
provided by plant biomass, e.g. cereals, perennial
grasses, maize, other energy crops or biomass from
unused agricultural areas. It is recommended to
include in feedstock, a part of manure, the different
local biomass, e.g. maize, perennial grasses and
legumes, straw, reed, waste biomass from food
industry, biodegradable part of municipal wastes,
aiming to increase economical viability for potential
biogas projects and to provide stable round year
running of biogas cogeneration plants.
III.
SYSTEM DESIGN
The system was designed by calculating
monthly demand of electrical energy required by a
small community in remote area as well as power
output of the different solar PV-wind turbine generator
combinations. Following points were taken into
account in system design [2, 3]:
 The power generated from PV and biomass
combination has to meet the total load of the
system. Energy required for water heating of the
community is provided by the solar water heater.
 Short term electrical power storage using leadacid batteries is considered. The size of battery
bank is worked out to substitute the PV array
during cloudy and no-sun days.
 Life time of battery bank is considered to be 5
years. This point is important when estimating the
capital costs.
 The storage battery bank will be able to supply
power during a maximum of 5 days on no-sun
days.
 The AC power from the inverter of the system is
fed to the distribution network of the community.
i. Optimization Analysis of the Hybrid System
HOMER performs the optimization process
in order to determine the best configuration of hybrid
renewable energy System based on several
combinations of equipments. Hence, multiple
possible combinations of equipments could be
obtained for the hybrid renewable energy system
due to different size of PV array and biomass system,
number of batteries and size of DC-AC converter.
Each and every combination of the system
configuration can be optimized by simulating it in the
search space. The feasible one will be d i s p l a y e d at
optimization r e s u l t sorted based on the Total Net
Present Cost (TNPC).
The main feature of optimization is to know
the optimized value and to meet the load and the entire
load has to be supplied by the PV-biomass system for
the entire year without depending on grid[6].
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Smruti Ranjan Pradhan et al Int. Journal of Engineering Research and Application
ISSN : 2248-9622, Vol. 3, Issue 6, Nov-Dec 2013, pp.433-437
ii. Modeling of PV and Biomass:
a) PV System: In order to efficiently and
economically utilize the renewable energy resources,
one optimum match design sizing method is
necessary. The sizing optimization method can help to
guarantee the lowest investment with adequate and
full use of the solar system, biomass system and
battery bank, so that the hybrid system can work at
optimum conditions in terms of investment and system
power reliability requirement[7]. Various optimization
techniques such as the probabilistic approach,
graphical construction method and iterative technique
have been recommended by researchers.
Power output from PV array: For design of a PV
system, we should know how much solar energy is
received at the concern place. It is effected by sun
position, could covering atmospheric affect, and the
angle at which the collector is placed, called tilt angle
‘β’. Normally this angle is equal to the latitude of the
concern place. The related equation for estimation of
the radiation is listed below:
1. Isolation
i = Io { cos ϕ cos δ cos ω + sin ϕ sin δ } kW/m2
2. Io = Isc [1 + 0.033 cos (360N/365)] where I sc solar
constant. =1.37 kW/m2
3. HoA = energy falling on t 3. H = ∫i dt ω = hour
o
sr
angle when sun rising
ω = hour angle when sun setting
ss
= (24/π) I [1+ 0.033 cos (360N/365)] {cos ϕ cos δ
sc
2
cos ω + sin ϕ sin δ} kWh/m /day he concern place
considering atmospheric effect
= KT Ho kWh/m2/day where KT dearness index
4. H = energy falling on the concern place
oA
considering atmospheric effect
2
= K H kWh/m /day where K dearness index
T
o
T
5. K = A1 + A sin (t) + A sin (2t) + A sin (3t) +A
T
2
3
4
5
cos (t) +A cos (2t) +A cos (3t)
6
7
st
t = (2π/365) (N-80) N= 1 for Jan 1
Wpeak = {1/ hpeak } [ (Wh((load) * No. of no sun days /
(ηb * no of discharging . Days)) + Whload(day) +
Whload(night)/ ηb)]
Where: ηb = battery efficiency
hpeak = no of hours for which peak insolation falls on
the PV cell.[8]
b) Biomass: Manure output from livestock in a year
will be calculated as follows:
Where,
M- Livestock (animals and crops residues) manure
produced in remote area, t.
n- average number of livestock present year-round
within ith group of livestock
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Ni- Number of specified groups of livestock
population in remote area,
mi- manure produced per one head in a year in the ith
group of livestock, t,
Biogas production from manure potential was
calculated as the sum of biogas volumes obtainable
from manure produced by animals and crop residues
in that area:
Where,
VB- biogas volume, potentially obtainable from
manure biomass in parish (municipality, region)
in a year, m3,
KDMi- dry matter content in manure produced by ith
group of animals
KOmi- organic matter content in dry matter of manure
produced by ith group of animals
VOmi- specific biogas output from manure organic
matter for ith group of animals
Energy of biogas obtainable from manure biomass in
municipality (region) was calculated as follows:
Where,
EB- energy potential obtainable from biogas produced
from manure, kWh
ebi- specific heat energy content of biogas obtained
from manure produced by ith group of animals,
kwh/m3[3,10].
IV.
SIMULATION WITH HOMER SOFTWARE
Homer is an abbreviation of “Hybrid
Optimization Model for Electric Renewables.” It is a
micro power optimization model developed and
regularly improved by the American National
Renewable Energy Laboratory. This software helps to
find the best electricity generation system
configuration that is to say the appropriated
technologies, the size and number of each component,
also comparing costs and environmental impacts. It
models both conventional and renewable energy
technologies in particular solar photovoltaic and wind
turbines which are the options envisaged for energy
efficient technologies. Homer is able to evaluate
economics and technical feasibility of the system. First,
Homer simulates the working power system by
calculating the hourly energy balance for a year. Hour
by hour, Homer determines the electric demand of the
site and the local electricity supplied by the system.
Comparing these energy flows, Homer is able to
estimate if the configuration is feasible that is to say if
the system can satisfy the electricity requirements.
Then, Homer optimizes the results. Among the
possible configurations defined by the simulation,
Homer retains the most cost-effective in a table ranked
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Smruti Ranjan Pradhan et al Int. Journal of Engineering Research and Application
ISSN : 2248-9622, Vol. 3, Issue 6, Nov-Dec 2013, pp.433-437
by Net Present Costs (NPC). Homer can realize a
sensitivity analysis by modifying some inputs in a
range defined by the user in order to compare different
possible scenarios [11]
i. Arrangement of sources and load
Fig.1: Basic setting of loads and sources in Homer
The main feature of simulation in Homer is
selecting the suitable sizes of the sources to meet the
daily load curve pattern of the system. As shown in
“Fig. 1” the load is having an average load of
20kwh/day and the peak load is 3.6kw. Hence the size
of the PV, biomass generator, battery and converter
are matched with the load patterns.
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Fig. 4: Solar location data entry
Fig. 5: Solar yearly radiation
Fig. 6: Percentage share of PV-Biomass
Fig. 2: Daily load profile
Fig.7: Yearly share of PV-Biomass
Fig. 3: Monthly load profile
The “fig.2 and 3” shows the daily and yearly
load curve of the consumer. Once the load profile has
uploaded in to the Homer software, the software
simulates according the availability of the solar power.
But it will depend on the availability of solar power in
a given area.
The main feature of the Homer software is it
will gives the availability of solar insolation once the
area latitude and longitude has given as shown in the
“fig.4”. Once the solar power source is available for
load pattern; then schedule of the solar power is
available and at what time periods the solar PV will
works also available. The remaining time periods the
biomass generator has to be operated.
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By observing “Fig.6 & 7” the load met by PV
array has 6,292 kwh/year and biomass is 3,845
kwh/yr. In other words the percentage shared by PV
array is 62 and by biomass is 38%. The care should be
taken that the dependence on PV array should be more
and biomass will be less. Because initially the PV
array cost is high but, the operation and maintenance
cost of PV array for the life span of 25 years will be
almost nil except the change of batteries for every 5
years. In case of biomass generator the initial cost of
the generator is less, but every day procuring the 0.
250 tons of biomass feed and the maintenance and
operation of biomass for the 25 years will be more.
The initial cost of the PV and biomass is
around 900,000 Rs/- and the total no. of units
generated from the system is 10,136 kwh/year and the
commercial rate of one unit is 7Rs/-. Hence the
payback period is comes around 12 years. But,
considering the subsidies of the government of about
50%, the payback period will reduces to 6 years. The
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